Migraine in transient global amnesia: a meta-analysis of observational studies

BACKGROUND

PURPOSE: Although many studies have investigated the relationship between transient global amnesia (TGA) and migraine, to date, no meta-analysis has confirmed the existence and size of their association.

METHODOLOGY

Literature search involved MEDLINE, EMBASE, CENTRAL and PsycINFO. Observational controlled studies including TGA patients (Caplan, Hodges and Warlow) were retrieved. Quality evaluation was based on the Newcastle-Ottawa scale. The prevalence of migraine was compared in TGA patients vs. healthy controls (HC), as well as in TGA against TIA individuals. Data from case-control, cross-sectional and cohort studies were pooled separately.

RESULTS

Literature search yielded 1178 articles, 12 of which were included in the present meta-analysis. Results from case-control (ten), cohort (one) and cross-sectional (one) studies were compatible with an association between TGA and migraine. The nationwide inpatient cross-sectional study was of lesser value due to its inpatient orientation. The high-quality, population-based, retrospective cohort (158,301 participants per group) determined a higher relative-risk (RR) of TGA for migraine vs. non-migraine individuals [RR = 2.48, 95%confidence-interval (95% CI) = (1.32, 4.87)]. Sensitivity testing based on stricter diagnostic criteria strengthened the estimated association [RR = 3.84, 95% CI = (1.57, 9.38)]. Additionally, pooled data from eight case-control studies (700 TGA, 746 HC) yielded similar results [Odds-Ratio, OR = 2.51, 95% CI = (1.85, 3.41)], with the association mainly driven by the three high-quality studies, rather than the five articles of moderate quality. Finally, pooled findings from four case-control studies of moderate-quality revealed a higher prevalence of migraine among TGA compared to TIA patients [OR = 1.82, 95% CI = (1.22, 2.73)].

CONCLUSIONS

A significant association between TGA and migraine was established. The underlying connecting mechanism remains undetermined, yet.

Differential Expression of Cytokine-Coding Genes among Migraine Patients with and without Aura and Normal Subjects

Migraine is a prevalent disorder in humans and represents one of the top 10 causes of years lived with disability. Several genetic and environmental factors are involved in the pathobiology of migraine. A number of studies have underscored the role of dysregulated immune reactions. We compared the expression levels IL-2, IL-4, CXCL8, IL-17, IFN-γ, TGF-β and TNF-α cytokines in blood specimens of patients with migraine and those of healthy persons to identify any possible dysregulation in their expression and to propose mechanisms for this disorder. Expression of INF-γ was suggestively higher in migraine cases than in healthy individuals (posterior beta = 0.35, adjusted P value = 0.017). In addition, expression of this cytokine was lower in female subjects than in male subjects (posterior beta = -0.712, adjusted P value = 0.012). Expression of IL-4, TGF-β and TNF-α was also higher in cases compared with controls (posterior beta = 1.34, adjusted P value = 0.04; posterior beta = 0.849, adjusted P value = 0.036; posterior beta = 0.451, adjusted P value = 0.042, respectively). On the other hand, CXCL8 expression was lower in migraine cases than in controls (posterior beta = -0.78, adjusted P value = 0.039). Expression levels of IL-1B, IL-17 and IL-2 were not meaningfully different between cases and controls. The current study highlights the dysregulation of cytokine-coding genes in the blood of patients with migraine.

Ubrogepant to treat migraine

Migraine is the primary headache disorder affecting a significant population worldwide. Ubrogepant is an orally bioavailable calcitonin gene-related peptide (CGRP) receptor antagonist (gepant) approved by the U.S. Food and Drug Administration (FDA) for the acute treatment of migraine headaches with or without aura in adults. Ubrogepant is the first oral CGRP receptor antagonist approved for the acute treatment of migraine. CGRP is an important key mediator of migraine pain; CGRP levels have been shown to be significantly higher during a migraine attack. Two pivotal phase III clinical trials (ACHIEVE I and ACHIEVE II) demonstrated effectiveness and safety of ubrogepant in acute migraine attacks. Ubrogepant can be administered as 50- and 100-mg tablets, with a maximum dose of 200 mg within 48 h. Besides minimizing pain, the drug is equally effective in alleviating migraine-associated symptoms such as nausea, photophobia and sound sensitivity. Unlike other gepants, ubrogepant is free from hepatotoxicity at the therapeutic doses. In certain cases (1 in 5), a full relief of pain was achieved with a single dose of the drug. The molecule is not effective as a preventive migraine therapy. The present review discusses the background, preclinical and clinical pharmacology, indication and safety of ubrogepant for the treatment of migraine attacks.

Nasal pain as an aura: Amygdala origin?

PURPOSE

Nasal pain, as an epileptic aura, has been poorly recognized. This study aims to demonstrate clinical features of patients with epilepsy who have nasal pain as an aura.

METHODS

We retrospectively investigated consecutive patients who visited the epilepsy clinic of tertiary hospital from April 2000 to September 2019. All included patients underwent epilepsy-dedicated, high-resolution magnetic resonance imaging (MRI) examinations. All MRI studies were analyzed by visual inspection.

RESULTS

Seven patients who presented nasal pain as an aura, were identified. Four patients reported nasal pain as the first aura. Four patients had right amygdala enlargement (isolated amygdala enlargement in three patients; amygdala enlargement in addition to hippocampal sclerosis in one patient), and one patient with compression of an internal carotid-posterior communicating artery aneurysm to right amygdala on brain MRI. Interictal epileptiform or ictal discharges on EEG were found in the right temporal region in five patients. In all four patients with amygdala enlargement, amygdala enlargement was ipsilateral to EEG anomalies. In all patients, nasal pain was accompanied by ictal semiological features, such as autonomic, olfactory, abdominal, or psychic auras, and focal impaired awareness seizures, which are typically associated with mesial temporal lobe epilepsy.

CONCLUSIONS

Our findings suggest that nasal pain can occur as an epileptic aura in patients with temporal lobe epilepsy with probable involvement of the amygdala.

Preoperative sensory aura predicts risk for seizure in temporal lobe epilepsy surgery

BACKGROUND

Patients with temporal lobe epilepsy (TLE) often report viscerosensory and experiential auras, with substantial epilepsy localization. However, few previous studies have investigated the epileptic preoperative aura, particularly with regard to its effect on surgical outcomes in patients with drug-resistant epilepsy.

OBJECTIVE

This study investigated the potential role of preoperative aura in predicting outcomes after surgery for TLE.

MATERIAL AND METHODS

This study included consecutive patients diagnosed with TLE who underwent anterior temporal lobectomy (ATL) for drug-resistant TLE during the period from January 1999 to December 2017. Data pertaining to patient age at the time of surgery, sex, age at initial seizure onset, duration of epilepsy, presence of preoperative aura, comprehensive clinical semiology, side of surgery, and type of pathology were analyzed. Preoperative auras were classified as autonomic, sensory, mental and affective, or multiple manifestations. Patients were followed at 3 and 12 months after surgery and at regular intervals thereafter.

RESULTS AND CONCLUSIONS

A total of 498 patients were included in the study. Positive preoperative aura was observed in 386 patients (77.51%). The correlation of each variable with seizure outcomes was analyzed, and the only variable found to correlate with seizure outcome was the presence of preoperative aura. Compared with those with negative preoperative aura, those with positive preoperative aura were 1.74-fold more likely to be seizure-free after surgery for TLE. The analysis of patient data suggested a later onset of initial seizure in those with positive preoperative aura, compared with those without (p = 0.04, 95% confidence interval (CI): 0.55-3.24). Patients with a shorter duration of disease prior to TLE surgery were more likely to achieve seizure-free status postoperatively. Preoperative sensory aura was a good predictor that a patient would be seizure-free during follow-up (p = 0.022).

Pediatric Migraine Phenomena and Variants: Don't Let Them Go Over Your Head

PURPOSE OF REVIEW

Primary care providers, general pediatric neurologists, and other related subspecialty providers require a clear understanding of pediatric migraine with typical aura and its variants.

RECENT FINDINGS

We highlight some of the genetic mutations known to contribute to specific types of migraine with aura, discuss the ophthalmologic phenomena of migraine and call attention to some of the earliest manifestations of migraine in children, many of which have correlates in adulthood. While the majority of headaches in children are migraine with or without aura or tension type, many migraine and aura variants exist. Early and accurate diagnosis of episodic syndromes associated with migraine, as defined by the 2018 ICHD-3 criteria, can help to reduce unnecessary imaging, referrals, cost and anxiety, thereby benefiting patients and their families.

Therapeutic implications of cortical spreading depression models in migraine

Migraine is among the most common and disabling neurological diseases in the world. Cortical spreading depression (CSD) is a wave of near-complete depolarization of neurons and glial cells that slowly propagates along the cortex creating the perception of aura. Evidence suggests that CSD can trigger migraine headache. Experimental models of CSD have been considered highly translational as they recapitulate migraine-related phenomena and have been validated for screening migraine therapeutics. Here we outline the essential components of validated experimental models of CSD and provide a comprehensive review of potential modulators and targets against CSD. We further focus on novel interventions that have been recently shown to suppress CSD susceptibility that may lead to therapeutic targets in migraine.

Genetics of migraine aura: an update

Migraine is a common brain disorder with a large genetic component. Of the two main migraine types, migraine with aura and migraine without aura, the genetic underpinning in the former is least understood. Given the evidence from epidemiological studies in cohorts and families that the genetic contribution is highest in migraine with aura, this seems paradoxical. Various genetic approaches have been applied to identify genetic factors that confer risk for migraine. Initially, so-called candidate gene associations studies (CGAS) have been performed that test DNA variants in genes prioritized based on presumed a priori knowledge of migraine pathophysiology. More recently, genome-wide association studies (GWAS) tested variants in any gene in an hypothesis-free manner. Whereas GWAS in migraine without aura, or the more general diagnosis migraine have already identified dozens of gene variants, the specific hunt for gene variants in migraine with aura has been disappointing. The only GWAS specifically investigating migraine with aura yielded only one single associated single nucleotide polymorphism (SNP), near MTDH and PGCP, with genome-wide significance. However, interrogation of all genotyped SNPs, so beyond this one significant hit, was more successful and led to the notion that migraine with aura and migraine without aura are genetically more alike than different. Until now, most relevant genetic discoveries related to migraine with aura came from investigating monogenetic syndromes with migraine aura as a prominent phenotype (i.e. FHM, CADASIL and FASPS). This review will highlight the genetic findings relevant to migraine with aura.

Migraine Pathophysiology

Migraine is the leading cause of years lost due to disability in individuals aged 15 to 49 years. Much has changed over the last three decades about our understanding of this complex neurological disorder. Various phases of migraine have been characterized and are the focus of this review. The premonitory phase involves bothersome symptoms experienced hours to days before migraine pain. Behavioral changes and functional neuroimaging studies point toward hypothalamic involvement during the premonitory and other migraine phases. Migraine aura is a disruptive, reversible neurological phenomenon that affects up to one-third of all migraineurs, and can overlap with the headache phase. The mechanism responsible for this phase is thought to be cortical spreading depolarization through the cortex. This process leads to temporary disruptions in ion homeostasis and the ensuing neuronal dysfunction. The headache phase involves activation of the trigeminocervical complex. Neuropeptides are implicated in trigeminal activation, and calcitonin gene-related peptide in particular has become a promising target of therapeutic intervention for migraine. The final phase of migraine is the postdrome, the period of time from the resolution of headache symptoms until return to baseline following a migraine. People often report neuropsychiatric, sensory, gastrointestinal, and general symptoms during this time, which can limit activity. Elucidating the neuroanatomical, chemical, and neuroimaging correlates of these migraine phases allows for an improved comprehension of the underlying changes associated with migraine symptomatology and can assist with evaluation of arising therapeutics for migraine management.

An Update: Pathophysiology of Migraine

Migraine is the most common disabling primary headache globally. Attacks typically present with unilateral throbbing headache and associated symptoms including, nausea, multisensory hypersensitivity, and marked fatigue. In this article, the authors address the underlying neuroanatomical basis for migraine-related headache, associated symptomatology, and discuss key clinical and preclinical findings that indicate that migraine likely results from dysfunctional homeostatic mechanisms. Whereby, abnormal central nervous system responses to extrinsic and intrinsic cues may lead to increased attack susceptibility.

Brain morphologic abnormalities in migraine patients: an observational study

Background

Migraine is a common neurological disorder characterized by a complex physiopathology. We assessed brain morphologic differences in migraine and the possible pathogenetic mechanism underlying this disease.

Methods

We analyzed brain morphologic images of migraine patients, 14 with aura (MwA) [the mean (SD) age was 42.36 (2.95) years (range, 37–47)] and 14 without aura (MwoA) [the mean (SD) age was 43.5 (3.25) years (range, 39–50)] during episodic attack compared with health subjects balanced (HS) [the mean (SD) age was 42.5 (5.17) years (range, 34–51)]. All subjects underwent a Magnetic Resonance Imaging (MRI) examination with a scanner operating at 3.0 T and voxel based morphometry (VBM) approach was used to examine the gray matter volume (GMV). The statistical analysis to compare clinicl characteristics was performed using unpaired t-test an one-way Anova. Results: Total cerebral GMV showed a significant difference between MwA and HS (p = 0.02), and between MwoA and HS (p = 0.003). In addition, not significative differences were found between MwA and MwoA groups (p = 0.17). We found three clusters of regions which showed significant GMV reduction in MwA compared with MwoA. MwA subjects showed a less of GMV in 4 clusters if compared with HS, and MwoA subjects showed a less of GMV in 3 clusters if compared with HS. We observed that MwA and MwoA patients had a significant reduction of GMV in the frontal and temporal lobe and the cerebellum, if compared to HS. The bilateral fusiform gyrus and the cingulate gyrus were increase in MwoA patients compared with HS.

Conclusion

Our findings could provide a approach to understand possible differences in the pathogenesis of two type of migraine.

Is there an association between NC_012920.1: m.8277T> C mitochondrial variation the mt-NC7 locus, and migraine with aura?

BACKGROUND

The molecular basis of migraines is still not completely understood. Over the last 30 years, mitochondrial dysfunction has been postulated as a potential mechanism in migraine pathogenesis. This study aimed to determine whether maternal mitochondrial variation was associated with migraines with aura.

METHODS

In this cross-sectional study, 50 individuals, who had been diagnosed with migraines with aura between January 2016 and July 2018 in the Neurology Department of the University Medical Faculty, and 50 healthy controls were recruited. Genomic DNA was isolated from the Ethylenediaminetetraacetic acid (EDTA) blood samples of the patients and the controls using the Easy One automated DNA isolation system. Mitochondrial DNA (mtDNA) libraries were prepared according to the Nextera XT DNA library-preparation protocol, and they were sequenced on the MiSeq platform (Illumina Inc., San Diego, CA, USA).

RESULTS

In the patient and control groups' analysis, 13 mtDNA variations were determined to be significantly different (p <0.05). The CC genotype for NC_012920.1: m.8277T>C variation was found to be higher in the patient group than the control group (p =0.001). The mtDNA NC_012920.1: m.8277T>C variation was significantly associated with the presence of neurological disease in the patient's family (p =0.043).

CONCLUSIONS

The present study is the first to demonstrate an association between mitochondrial dysfunction and the susceptibility to migraine with aura in individuals carrying the NC_012920.1: m.8277T>C variation. Knowing the level of cytochrome C oxidase and oxidative phosphorylation corruption in these patients may be predictive in understanding the phenotype/genotype relationship. Thus, mtDNA variations may contribute to the pathogenesis of migraines with aura. HIPPOKRATIA 2020, 24(2): 59-65.

The Relationship between Aura and Postoperative Outcomes of Epilepsy Surgery in Patients with Mesial Temporal Sclerosis

BACKGROUND

We conducted a study to evaluate the relationship between aura types and postoperative outcomes in patients with mesial temporal sclerosis (MTS) to predict the prognosis of patients, accordingly.

MATERIALS AND METHODS

In this cross-sectional study, 99 patients with MTS-temporal lobe epilepsy were enrolled based on inclusion and exclusion criteria. The types of aura were evaluated, and the outcomes were categorized according to the Engel scale. Preoperative and postoperative results of patients were compared and analyzed with the Kruskal-Wallis test.

RESULTS

About 73.7% of patients had seizure-free after their surgeries. The most of patients (n = 81) were in Class I of Evaluating Engel criteria. About 36.3% had not experienced any aura before their seizures, and among those with aura, the most prevalent aura was abdominal aura in 29 patients (29.3%) followed by other types of aura and affective aura. Most of the patients in Class I, II, III, and IV of Engel scale had an abdominal aura, without aura, effective aura, and abdominal aura, respectively, but this difference was not statistically significant (P = 0.691).

CONCLUSION

According to this study, the type of aura cannot predict postoperative outcomes in MTS patients. More studies are needed to evaluate this relation in better-planned studies with greater sample size.

Cholinergic modulation inhibits cortical spreading depression in mouse neocortex through activation of muscarinic receptors and decreased excitatory/inhibitory drive

Cortical spreading depression (CSD) is a wave of transient network hyperexcitability leading to long lasting depolarization and block of firing, which initiates focally and slowly propagates in the cerebral cortex. It causes migraine aura and it has been implicated in the generation of migraine headache. Cortical excitability can be modulated by cholinergic actions, leading in neocortical slices to the generation of rhythmic synchronous activities (UP/DOWN states). We investigated the effect of cholinergic activation with the cholinomimetic agonist carbachol on CSD triggered with 130 mM KCl pulse injections in acute mouse neocortical brain slices, hypothesizing that the cholinergic-induced increase of cortical network excitability during UP states could facilitate CSD. We observed instead an inhibitory effect of cholinergic activation on both initiation and propagation of CSD, through the action of muscarinic receptors. In fact, carbachol-induced CSD inhibition was blocked by atropine or by the preferential M1 muscarinic antagonist telenzepine; the preferential M1 muscarinic agonist McN-A-343 inhibited CSD similarly to carbachol, and its effect was blocked by telenzepine. Recordings of spontaneous excitatory and inhibitory post-synaptic currents in pyramidal neurons showed that McN-A-343 induced overall a decrease of the excitatory/inhibitory ratio. This inhibitory action may be targeted for novel pharmacological approaches in the treatment of migraine with muscarinic agonists.

Surgical Prognostic Value of Epileptic Aura Based on History and Electrical Stimulation

Background and Purpose

We attempted to evaluate the surgical prognostic value of various types of aura in conjunction with the results of other presurgical evaluations in patients with an intracranial ictal onset zone confirmed by invasive studies and focal resection. We also attempted to determine how often the habitual auras could be elicited and to demonstrate the prognostic value of these stimulation-induced auras (SIAs).

Methods

We reviewed retrospectively the records of patients who had undergone intracranial electroencephalography evaluation and focal resective surgery for intractable partial epilepsy between 1995 and 2009. We identified the localizing value and prognostic value of the patients’ auras. We correlated the resection of the area with SIA and surgical outcome.

Results

Aura was reported in 225 out of 300 patients. Patients with medial temporal lobe epilepsy (TLE) or occipital lobe epilepsy had a higher chance of having aura. The presence of aura, medial TLE, hippocampal sclerosis on pathology, focal lesions on magnetic resonance imaging (MRI), and ipsilateral abnormality on fluorodeoxyglucose-positron emission tomography were significantly correlated with seizure-free outcome. The presence of auditory aura, parietal lobe epilepsy, multifocal epilepsy, and dual pathology was associated with poor outcomes. Multivariate analysis revealed that auditory aura, multifocal epilepsy, hippocampal sclerosis, and lesion on MRI were prognostic factors for intractable partial epilepsy. SIA was observed in 29 out of the 134 patients who had habitual aura on history. The degree of complete resection of the area with SIA was not related to seizure-free outcome.

Conclusions

The presence of aura favors good surgical outcome and certain types of aura, such as auditory aura, have poor prognostic value. SIA, which was encountered in 21.6% of patients, was not related to seizure-free outcome.

Differences in early and late pattern-onset visual-evoked potentials between self- reported migraineurs and controls

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Migraineurs had an enhanced N2 evoked by gratings with a spatial frequency of 13 cpd.

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Migraineurs had an attenuated occipital late negativity (LN) for viewing all gratings.

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Hyperexcitable controls showed similar VEP pattern compared to migraineurs.

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Enhanced N2 deflection could be driven by cortical hyperexcitation.

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LN reduction could reflect inhibitory control during processing of aversive stimuli.

Striped patterns have been shown to induce strong visual illusions and discomforts to migraineurs in previous literature. Previous research has suggested that these unusual visual symptoms to be linked with the hyperactivity on the visual cortex of migraine sufferers. The present study searched for evidence supporting this hypothesis by comparing the visual evoked potentials (VEPs) elicited by striped patterns of specific spatial frequencies (0.5, 3, and 13 cycles-per-degree) between a group of 29 migraineurs (17 with aura/12 without) and 31 non-migraineurs. In addition, VEPs to the same stripped patterns were compared between non-migraineurs who were classified as hyperexcitable versus non-hyperexcitable using a previously established behavioural pattern glare task. We found that the migraineurs had a significantly increased N2 amplitude for stimuli with 13 cpd gratings but an attenuated late negativity (LN: 400 – 500 ms after the stimuli onset) for all the spatial frequencies. Interestingly, non-migraineurs who scored as hyperexcitable appeared to have similar response patterns to the migraineurs, albeit in an attenuated form. We propose that the enhanced N2 could reflect disruption of the balance between parvocellular and magnocellular pathway, which is in support of the cortical hyperexcitation hypothesis in migraineurs. In addition, the attenuation of the late negativity could reflect a top-down feedback mechanism to suppress visual processing of an aversive stimulus.

Transient Neurologic Dysfunction in Migraine

Transient disturbances in neurologic function are disturbing features of migraine attacks. Aura types include binocular visual, hemi-sensory, language and unilateral motor symptoms. Because of the gradual spreading quality of visual and sensory symptoms, they were thought to arise from the cerebral cortex. Motor symptoms previously included as a type of migraine aura were reclassified as a component of hemiplegic migraine. ICHD-3 criteria of the International Headache Society, added brainstem aura and retinal aura as separate subtypes. The susceptibility to all types of aura is likely to be included by complex and perhaps epigenetic factors.

Aura and Head pain: relationship and gaps in the translational models

Migraine is a complex brain disorder and initiating events for acute attacks still remain unclear. It seems difficult to explain the development of migraine headache with one mechanism and/or a single anatomical location. Cortical spreading depression (CSD) is recognized as the biological substrate of migraine aura and experimental animal studies have provided mechanisms that possibly link CSD to the activation of trigeminal neurons mediating lateralized head pain. However, some CSD features do not match the clinical features of migraine headache and there are gaps in translating CSD to migraine with aura. Clinical features of migraine headache and results from research are critically evaluated; and consistent and inconsistent findings are discussed according to the known basic features of canonical CSD: typical SD limited to the cerebral cortex as it was originally defined. Alternatively, arguments related to the emergence of SD in other brain structures in addition to the cerebral cortex or CSD initiated dysfunction in the thalamocortical network are proposed. Accordingly, including thalamus, particularly reticular nucleus and higher order thalamic nuclei, which functions as a hub connecting the visual, somatosensory, language and motor cortical areas and subjects to modulation by brain stem projections into the CSD theory, would greatly improve our current understanding of migraine.

Retinal vascular density evaluation of migraine patients with and without aura and association with white matter hyperintensities

Underlying pathophysiological mechanism of migraine is not all clear; however, recent reports suggested that neurovascular system is involved. We aimed to evaluate the retinal vessel densities of migraine patients with and without aura and the associations with white matter hyperintensities (WMH), using optical coherence tomography angiography (OCTA). We recruited 28 migraine with aura (MWA) patients, 26 migraine without aura (MWO) and age and sex-matched 34 healthy controls in our study. All participants were evaluated with optical coherence tomography (OCT) and OCTA for optic nerve parameters and retinal vessel densities with RTVue XR AVANTI. On macular OCTA, superficial and deeper retinal foveal vessel density (VD) were significantly lesser in MWA and MWO than controls. On optic nerve OCTA, whole optic disc, peripapillary, superior hemisphere, superior layer and temporal layer VD were significantly lesser in MWA and MWO. In group of MWA with the WMH, deeper foveal VD and superior hemisphere VD, average RNFL, superior hemisphere and superior layer were significantly lesser and also foveal avascular zone was significantly larger than the group of without WMH. Alterations of VD in patients with migraine are showed in our study. In addition, in group of MWA these alterations have associations with WMH. Supporting these findings with further reports can be useful to understand the pathophysiology of this disease.

Evidence for hyperprolactinemia in migraineurs: a systematic review and meta-analysis

BACKGROUND

One of the hypothalamus-pituitary axis hormones which may play a crucial role in pathophysiology of migraine is prolactin which is secreted from anterior pituitary gland and synthesized by various immune system cells as well. Whether prolactin blood levels can affect the migraine pathogenesis is an open question. Therefore, investigating prolactin circulatory levels in migraineurs may pave the way to underpin the mechanisms of migraine pathophysiology at biochemical levels. In the current investigation, the prolactin blood levels in the migraine subjects were investigated using systematic review and meta-analysis.

METHODS

Using online and specialized biomedical databases including Google Scholar, Medline, Pubmed, Pubmed Central, Embase, and Scopus, without the beginning date restriction until Feb 2019, the systematic review retrieved 11 publications in this systematic review after fulfilling for the inclusion and exclusion criteria. For heterogeneity, extent calculation statistical testing was applied. In the present study, the levels of circulatory prolactin in migraineurs assessed using standardized mean difference (SMD) as the effect size.

RESULTS

Q quantity and I²% statistic index showed a high heterogeneity in the 13 selected publications (188.370 and 92.568, respectively) and random-effects model was chosen for further analyses. The meta-analysis on a total number of 460 migraineurs and 429 healthy controls found that the weighted pooled SMD for the effects of prolactin blood concentrations on migraine pathogenesis was as follows: SMD = 1.435 (95% confidence interval, 0.854-2.015).

CONCLUSION

The current investigation presents evidence that prolactin blood levels are higher in migraineurs than healthy subjects.

Aura and Stroke: relationship and what we have learnt from preclinical models

BACKGROUND

Population-based studies have highlighted a close relationship between migraine and stroke. Migraine, especially with aura, is a risk factor for both ischemic and hemorrhagic stroke. Interestingly, stroke risk is highest for migraineurs who are young and otherwise healthy.

MAIN BODY

Preclinical models have provided us with possible mechanisms to explain the increased vulnerability of migraineurs' brains towards ischemia and suggest a key role for enhanced cerebral excitability and increased incidence of microembolic events. Spreading depolarization (SD), a slowly propagating wave of neuronal depolarization, is the electrophysiologic event underlying migraine aura and a known headache trigger. Increased SD susceptibility has been demonstrated in migraine animal models, including transgenic mice carrying human mutations for the migraine-associated syndrome CADASIL and familial hemiplegic migraine (type 1 and 2). Upon experimentally induced SD, these mice develop aura-like neurological symptoms, akin to patients with the respective mutations. Migraine mutant mice also exhibit an increased frequency of ischemia-triggered SDs upon experimental stroke, associated with accelerated infarct growth and worse outcomes. The severe stroke phenotype can be explained by SD-related downstream events that exacerbate the metabolic mismatch, including pericyte contraction and neuroglial inflammation. Pharmacological suppression of the genetically enhanced SD susceptibility normalizes the stroke phenotype in familial hemiplegic migraine mutant mice. Recent epidemiologic and imaging studies suggest that these preclinical findings can be extrapolated to migraine patients. Migraine patients are at risk for particularly cardioembolic stroke. At the same time, studies suggest an increased incidence of coagulopathy, atrial fibrillation and patent foramen ovale among migraineurs, providing a possible path for microembolic induction of SD and, in rare instances, stroke in hyperexcitable brains. Indeed, recent imaging studies document an accelerated infarct progression with only little potentially salvageable brain tissue in acute stroke patients with a migraine history, suggesting an increased vulnerability towards cerebral ischemia.

CONCLUSION

Preclinical models suggest a key role for enhanced SD susceptibility and microembolization to explain both the occurrence of migraine attacks and the increased stroke risk in migraineurs. Therapeutic targeting of SD and microembolic events, or potential causes thereof, will be promising for treatment of aura and may also prevent ischemic infarction in vulnerable brains.

Advanced visual network and cerebellar hyperresponsiveness to trigeminal nociception in migraine with aura

Background

Despite the growing body of advanced studies investigating the neuronal correlates of pain processing in patients with migraine without aura (MwoA), only few similar studies have been conducted in patients with migraine with aura (MwA). Therefore, we aimed to explore the functional brain response to trigeminal noxious heat stimulation in patients with MwA.

Methods

Seventeen patients with MwA and 15 age- and sex-matched healthy controls (HC) underwent whole-brain blood oxygen level–dependent (BOLD) fMRI during trigeminal noxious heat stimulation. To examine the specificity of any observed differences between patients with MwA and HC, the functional response of neural pathways to trigeminal noxious heat stimulation in patients with MwA was compared with 18 patients with MwoA. Secondary analyses investigated the correlations between BOLD signal changes and clinical parameters of migraine severity.

Results

We observed a robust cortical and subcortical pattern of BOLD response to trigeminal noxious heat stimulation across all participants. Patients with MwA showed a significantly increased activity in higher cortical areas known to be part of a distributed network involved in advanced visual processing, including lingual gyrus, inferior parietal lobule, inferior frontal gyrus and medial frontal gyrus. Moreover, a significantly greater cerebellar activation was observed in patients with MwA when compared with both patients with MwA and HC. Interestingly, no correlations were found between migraine severity parameters and magnitude of BOLD response in patients with MwA.

Conclusion

Our findings, characterized by abnormal visual pathway response to trigeminal noxious heat stimulation, support the role of a functional integration between visual and trigeminal pain networks in the pathophysiological mechanisms underlying migraine with aura. Moreover, they expand the concept of “neurolimbic-pain network” as a model of MwoA including both limbic dysfunction and cortical dys-excitability. Indeed, we suggest a model of “neurolimbic-visual-pain network” in MwA patients, characterized by dysfunctional correlations between pain-modulating circuits not only with the cortical limbic areas but with advanced visual areas as well. Furthermore, the abnormal cerebellar response to trigeminal noxious heat stimulation may suggest a dysfunctional cerebellar inhibitory control on thalamic sensory gating, impinging on the advanced visual processing cortical areas in patients with MwA.

Electronic supplementary material

The online version of this article (10.1186/s10194-019-1002-3) contains supplementary material, which is available to authorized users.

Spreading depression as a preclinical model of migraine

Spreading depression (SD) is a slowly propagating wave of near-complete depolarization of neurons and glial cells across the cortex. SD is thought to contribute to the underlying pathophysiology of migraine aura, and possibly also an intrinsic brain activity causing migraine headache. Experimental models of SD have recapitulated multiple migraine-related phenomena and are considered highly translational. In this review, we summarize conventional and novel methods to trigger SD, with specific focus on optogenetic methods. We outline physiological triggers that might affect SD susceptibility, review a multitude of physiological, biochemical, and behavioral consequences of SD, and elaborate their relevance to migraine pathophysiology. The possibility of constructing a recurrent episodic or chronic migraine model using SD is also discussed.

Advanced Imaging in the Evaluation of Migraine Headaches

The use of advanced imaging in routine diagnostic practice appears to provide only limited value in patients with migraine who have not experienced recent changes in headache characteristics or symptoms. However, advanced imaging may have potential for studying the biological manifestations and pathophysiology of migraine headaches. Migraine with aura appears to have characteristic spatiotemporal changes in structural anatomy, function, hemodynamics, metabolism, and biochemistry, whereas migraine without aura produces more subtle and complex changes. Large, controlled, multicenter imaging-based observational trials are needed to confirm the anecdotal evidence in the literature and test the scientific hypotheses thought to underscore migraine pathophysiology.

Primary headaches during lifespan

Primary headaches are one of the most prevalent neurological disorders and can occur during a wide range of lifespan. Primary headaches, especially migraine, are cyclic disorders with a complex sequence of symptoms within every headache attack. There is no systematic review of whether these symptoms changes during lifespan. Indeed, the clinical presentation of migraine shows an age-dependent change with a significantly shorter duration of the attacks and occurrence of different paroxysmal symptoms, such as vomiting, abdominal pain or vertigo, in childhood and, in contrast, largely an absence of autonomic signs and a more often bilateral headache in the elderly. The age-dependent differences in the clinical presentation are less distinct in cluster headache and, especially, in tension-type headache. The differences in the clinical presentation are in agreement with the idea that the connectivity of hypothalamic areas with different brainstem areas, especially the central parasympathetic areas, is important for the clinical manifestation of migraine, as well as, the change during lifespan.